Apparatus for orienting well tools



Jan- 30, 1945. T. A. CRL-:lGHTON APPARATUS FOR ORIENTING WELL TOOLS Filed June 14, 1941 u@ W4 wa. ma i f f J z 9^ Z@ 4?? oar/J6 rlvl y H E Y Y w.- |nu d NHHHHIW,

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UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to operations in wells and relates more particularly to apparatus for orienting objects in wells. A general object of the invention is to provide a rapid dependable method and a simple, practical and inexpensive apparatus for orienting objects in wells.

In certain Well drilling operations and particularly in directional well drilling it is often necessary to orient objects in the wells. Various methods and apparatus have been introduced for carrying on such orienting operations. In most instances the devi-ces now employed are complicated and expensive and require the provision of expensive ttings or special parts in the well tool. Furthermore, many prior orienting methods depend upon an initial survey or determination of the inclination and direction of inclination of that part of the well bore in which the tool is to be set. Such determinations cannot be relied upon because the tool, when lowered to the selected portion of the well, seldom assumes a position in true axial alignment with the bore and subsequent operations and calculations depending for their accuracy upon the assumption that the tool is truly axial in the bore are many times erroneous.

Another object of this invention is to provide an apparatus for orienting a well tool which requires the use of only very simple equipment and does not necessitate the employment of complicated and costly fixtures or parts in the well tool.

Another object of this invention is to provide an orienting apparatus of the character referred to that does not depend upon the accuracy of a survey of the inclination of the well bore or of a determination of the exact inclination of the tool in the well bore and, therefore, is not subject to error by reason of errors in such operations.

Another object of this invention is to provide an orienting apparatus that is dependable and positive and which does not depend upon the functioning of delicate equipment.

Another object of this invention is to provide an apparatus of the character referred to that may be rapidly carried out Aand that provides an immediate readily ascertainable determination of the position of the well tool.

Another object of this invention is to provide apparatus for orienting a well tool that requires but very few inexpensive additions to the well tool and the surveying instrument.

A further object of this invention is to provide an apparatus of the chara-cter mentioned that may be employed on practically any form of well tool and that is capable of repeated reuse,

, The various objects and features of my invention will be readily understood from the following detailed description of a typical preferred form and application of my invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a fragmentary longitudinal section of a well string showing the upper portion of the surveying equipment therein. Fig. 2 is an enlai-ged longitudinal detailed sectional view of the well tool and adjacent parts showing the surveying instrument in position to take an initial reading or record. Fig. 3 is a. view similar to Fig. 2 showing the surveying instrument in position for the second operation or recording. Fig. 4 is an enlarged fragmentary diagrammatic view of the surveying instrument and Fig. 5 is a transverse detailed sectional view taken as indicated by line 5-5 on Fig. 2.

The improved method and apparatus of this invention may be employed in different well drilling operations and in the orientation of well tools and the like of various kinds. In the following detailed description I will set forth the invention as employed in the orientation of a whipstock, it being understood that this is merely a typical application and is not to be construed as limiting or restricting the invention.

The apparatus illustrated in the drawing may be said to comprise, generally, a drilling string S, a drill bit I0 on the string S, a whipstock II associated with the drilling tool I0, a surveying instrument I2 to be run down through the string S to the bit I0, and means I3 for causing the instrument I2 to incline in a given direction relative to the bit I 0 and whipstock I I.

The drilling string S may be a conventional string of rotary drill pipe assembled and run into the well in the usual way. 'I'he lower end of the string S is equipped with a sub I4. The sub I4 may be threaded on the lower end of the string S and has a socket or box I5 in its lower end. The drilling bit I0 may be any form of well drilling tool useful with the whipstock II. In the construction illustrated, the bit I0 is a tubular member having a central longitudinal opening I6 and provided at its lower end with cutting parts I'I. A pin I8 on the upper end of the bit I0 is threaded in the socket I5. .The upper end of the bit IIl forms an upwardly facing annular shoulder I9 at the lower end of the sub I4. The opening through the sub I4 may be of substantially the same diameter as the bit opening I 6 and the passage through the bit and sub are somewhat smaller in diameter than the interior of the string S, but is of substantial size or capacity.

The whipstock I I may be of any suitable or selected type. The whipstock, shown, is provided at its upper end with a ring 20 which engages around the sub I4 to rest on the shoulder I9. The body II of the whipstock extends downwardly beyond the bit I0. The whipstock has a concave inner face 2I sloping downwardly and inwardly toward the central longitudinal axis of the string and bit assembly. This is typical of whipstock structures and may be varied as required. In accordance with the invention the whipstock I I is temporarily or releasably secured to the lait I and string S to have a given or known rotative position with respect thereto. A rivet or shear pin 22 is passed inwardly through a radial opening in the ring Sand engages in an opening 23 in the sub I4 to detachably or releasably secure the whipstock II in a position where its inclined face 2| is in a known rotative position with respect to the bit I0 and string S. 'I'he pin 22 is formed to fail or shear 01T when the drilling operation is started.

The surveying instrument I2 may Ibe of the type known as single shots or may be of any other type operable to produce records of its degree of inclination and direction of inclination when in position in a well or in a well tool. Surveying instruments of this class are well known to those skilled in the art and a detailed description of the instrument I2 is unnecessary in the present disclosure. The surveying instrument I2 is an elongate element or assembly proportioned to freely pass through the drilling string S and to enter and .pass through the bit opening I6 with clearance leaving an annular space. The lower portion of the instrument I2 contains the recording elements. Fig. 4 of the drawing diagrammatically illustrates the typical elements of this class of surveying instrument. The elements include a magnetic compass needle 24 pivotally supported in the lower portion of the instrument case and a container or cell 25 mounted above the compass needle and containing a transparent liquid. A free bubble 26 is left in the container or cell 25. The portion of the surveying instrument I2 containing the magnetic compass needle 24 is usually shielded with non-magnetic material. Lamps 21 are arranged below shields in the instrument I2 to direct their light downwardly through the container 25 and to the needle 24. A sensitive plate or photographic plate 28 is spaced above the lamps 21 and a lens 29 is spaced between the lamps and the plate 28 to direct the reflected light from the needle 24 and bubble 28 to the sensitive plate 28. The lamps 21 are timed to illuminate the surveying instrument elements at a given time or at given times, this being the usual Imode of operation of this class of instrument. It will be apparent how the positions of the compass needle 24 and bubble 26 will be recorded on the sensitive plate 28. The surveying instrument I2 is adapted to be run into and out of the string S on a cable or wire line 30. In accordance with this invention the instrument I2 may include two separate record-producing mechanisms of the general type just described. For example, in the drawing A and B designate two such mechanisms, the mechanism A being adjacent the lower end of the instrument and the mechanism B ,being higher in the instrument. The mechanisms A and B are independently operable and separately timed.

The means I3 for controlling the position or inclination of the surveying instrument I2 is an I3 is operable to locate the surveying instrument I2 in a co-axial position in the bit III for the rst operation or survey recordation and is operable to give the instrument I2 an inclination in a known direction relative to the bit II) and string S for the second operation. The means I3 includes a weight element, jar or sinker bar 3| xed to the lower end of the line 30 as by a rope socket. The lower portion of the weight element or sinker bar 3I has a longitudinal opening 32 provided at its lower end with a bushing or guide 33. A flexible link or line 34 extends through the guide 33 and is xed to the instrument I2 as by a rope socket 35. A head 36 is provided on the upper end of the link or line 34 and a shock absorbing means 31 is arranged under compression between the head 36 and the inner end of the guide 33. With the structure just described the surveying instrument I2 is free to assume any position when suspended from the line 30, its position being determined by gravity and/ or by engagement with instrumentalities in the bit I0, sub I4, etc.

The means I3 further includes a centering and fulcrum ring 38 in the bit I0. The fulcrum ring 38 is preferably arranged in the lower portion of the bit I0. In the preferred construction the ring 38 is fixed in a socket or enlargement formed in the lower portion of the bit opening I6. The internal surface of the ring 38 is rounded or convex and the portion of the ring exposed in the opening I6 has a surface which curves downwardly and inwardly and then downwardly and outwardly. The ring 38 is proportioned to receive or pass the surveying instrument I2 with only slight clearance. In practice the lower end of the surveying instrument I2 is provided with a tapered or rounded guide 39 and the body or major portion of the instrument I2 is of uniform diameter throughout and rather closely or accurately iits the ring 38. When the surveying instrument I2 is lowered down through the string S to a position where its lower portion protrudes .beyond the bit III, as illustrated in Figs. 1 and 2, the ring 38 centralizes the surveying instrument in the bit IIJ and the ring, together with the suspension line 30, maintains the surveying instrument I2 where it is co-axial with the .bit III, sub

important feature of the invention. The means 76 I4 and the adjacent portion of the string S. It is to be observed that under the circumstances just mentioned the lower portion of the surveying instrument I2 may protrude a substantial distance beyond the .bit I0 without interference with the whipstock II so that the com-pass needle 24 is unaffected by immediately adjacent or surrounding metal parts of the equipment. This is important as will later become apparent.

The means I3 further includes cooperable parts on the surveying instrument I2 and string S adapted to cause the surveying instrument I2 to slope or incline in a known direction relative to the string S. The element on the surveying in'- strument I2 is a frusto-conical member or tapered member 40 positioned adjacent the upper end of the instrument I2 while the element on the string S may be a lug or projection 4I on the wall of the bit opening I6. The member 40 may be arranged adjacent or immediately below the head or rope socket 35 of the instrument I2. The member 40 is round or annular in transverse cross section and has a downwardly'and inwardly tapering external surface. As best illustrated in Fig. 3 of the drawing, the surveying instrument I2 is of substantial length and the member 4D is spaced a considerable d istanceabovethe QVJII biill EAI the'length of the member 40.

uunutui lower portion of the instrument I2 which con tainsthe needle 24, cell 25, etc.

The lug or projection 4| may be a part formed Y on or welded on the wall of the opening I5 or may be the head orend part of a pinor rivet 42 ar-d ranged in a radial opening 43 in the wall of the bit I0, as illustrated. The head or projection 4I ,1. prevents outward movement of the pin 42 and -the outer end of the pin may be peened over or riveted to prevent inward displacement of the pin. The lug or projection 4| preferably, thoughy not necessarily, has a rounded or partiallyr spherical surface for engagement by the member.

40 on the surveying instrument. The projectionv 4I may extend into the opening I6 a distance equal to the extent of inwardY projection of the,` ring 38 but should not project inwardly a greater distance. The lug or projection 4| is spaced some distance above the ring 39. The spacing of the projection 4I from the ring 38 is slightly less than In accordance 'with the invention the projection 4I is' in a given.. or known rotative position relative to the whipf stock II. In most cases it is preferred to locate the projection 4I in a plane 180 from the plane occupied by the Icentral longitudinal axis of the whipstock surface 2|. As will be later described theA cooperation of the tapered member 48 with the projection l4I causes the instrument I2 to incline in a known direction relative to the bit I0 and whipstock II when the instrument' is lowered and pressed down to cause the member 40 to be crowded between the pro-jection 4I andy the opposite wall of the opening I6.

The method of the invention as practiced with the apparatus described above comprises, generally, lowering the string S into the well to bring the whipstock II to the desired level, lowering the instrument I2 through the string S to assume a co-axial position in the bit I0 and causing the instrument to operate in that. posi.A tion to obtain a survey or record, later bringing the instrument I2 to a position Where it is inclined vin a known direction relative to the bit I0 and whipstock II and causing the instrument I2 to operate in the inclined position to produce a record and then determining from said readings or records the position or orientation of the whipstock I I.

-The string S carrying the bit I0 and the whipstock II is assembled and run into the well in the usual way. The string S is lowered to bring the whipstock II to the required level which, in most instances, is at the lower end of the well.

The instrument I2 isA then conditioned for opera- .f'

tion and run down through the string S on the line 30. Where the two recording mechanisms A and B are used the instrument A is set to operate at a given time and the mechanism B is set to operate a certain time after the operation of the mechanism A. The instrument I2 is lowered until it extends through the sub I4 and bit I0 to project beyond the lower end of the. bit. It will be observed that this brings the mechanism A clear of the bit IIJ, whipstock I I and other parts of the string of tools so that the compass needle 24 is unaffected by such parts. It is preferredl to leave the instrument I2 susel pendedon the line 30 so that it assumes a coaxiaipcsiuon in the bit lo and the iower 'part of the string' S. Fig. 2 of the drawing illustrates the instrument I2 in the position just described and illustrates the manner in which the fulcrum ring 39 centralizes the instrument. With the instrument in the position such as shown in Fig. 2

Room

the mechanism A operates or is caused to operate. This operation provides a record of the extent and direction of inclination, if any, of the bit I0 and the adjacent part of the string S. It will be observed that this record does not indicate or represent the inclination of the bore but discloses the true inclination and direction of inclination of the bit I0 and adjacent part of the string S. A survey or recording of the inclination of the well bore would not necessarily represent the inclination or direction of inclination of the bit I0 because well tools frequently lie at an angle in the bore. .If the instrument I2 has only one recording mechanism it is withdrawn from the well upon the completion of the operation just described and the reading or record is developed and the vinstrument is again conditioned for use. Where the instrument has the two mechanisms A and B it is allowed to remain in the well. y

'Ihe instrument I2 is now lowered until the member V4I) moves against the projection 4I. The weight or sinker bar 3| is allowed to rest on or is operated to strike downwardly againstl the rope socket 35. This drives or forces the instrument I2 downwardly so that the tapered member `4III is crowded between the projection 4I and the opposite wall of the bit opening I6. As illustrated in Fig. 3 of the drawing the projection 4I crowds the member v4I) to one side or toward the opposite wall of the opening IB. This results in pivoting or inclining of the entire surveying instrument I2. The ring 38 forms a fulcrum for the instrument I2. The portion of the instrument I2 above the V ring 38 forms one iarfm of :a lever and .the portion of the instrument extending below the ring 38 `forms theother arm of a lever. It is important to note that the cooperation of the tapered member 40 rwith the projection `4| tilts or inclines the instrument I 2 in a given or'known direction relative to the bit III and whipstock I I. Further, the cooperation of the member 40 with the projection 4I usually produces a known or given inclination of the instrumentI I2 with respect to the longitudinal axis of the bit I0. In the case illustrated the engagement of the tapered member 40 with the projection -4I results in the major lower portion of the instrument vI2 being inclined downwardly and away from the whipstock II in a plane substantially coincident lwith the central longitudinal plane of the whipstock. With the instrument I2 in the tilted or inclined position just described and illustrated in Fig. 3, the mechanism B operates or is caused to operate to record the position of the needle 24\ and the bnhblel'... The instrument I2 is then withdrawnfrom the well and the photographic records or plates 28 of the mechanisms A and B are developed.

The records produced by the two operations of the instrument I2 are compared andthe orientation of the whipstock |I is computed or determined from the two readings. The first record taken when the surveying instru-ment I-2 was coaxial lwith the bit I0 gives the actual or 4approximate inclination and direction of inclination of the fbitA II). The second record indicates the direction of inclination and the degree of inclina ti-on of the instrument I2 when tilted by the projection 4I Icooperating with the member 40. As the rotative position of the projectionA 4| relative to the whipstock II is known the second reading or record of itself may be used to ascertain the rotative or compass position of the whipstock II. For example, if the second record (made by the mechanism B) shows that the instrument I2 was inclined to the west it is apparent thatthe `whipstock which is approximately 180 from the plane of the projection 4I lies to the east. Thus, the rotative position or orientation of the 'whipstock II may be determined from the second record alone. However, as few deep wellsl are straight or vertical it is often preferred to produce and employ the first reading or record of the instru ment I2, that is, the record produced with the instrument in ,a position such asl shown in Fig. 2.

If this first record indicates that the bit I is substantially vertical or only slightly pitched with respect to the vertical the second reading mai be employed alone to determine the orientation of the iwhipstock I l. However, if the rst reading or record (obtained by the mechanism A) indicates that the bit I0 has a substantial inclination it is important to compare and relate the two records of the instrument I2 so that the inclination of the bit I0 will not cancel out the apparent inclination of the instrument I2 when in the position shown in Fig. 3 and so that the actual inclination of the bit IIJ will not make it appear that the instrument I2 is sloping in a direction other than the actual direction when the second record i-s taken with the instrument as sho-wn in Fig. 3. The two simple surveying operations or simple operations of the instrument I2 may be readily utilized to determine the true orientation of the whipstock I I. When the orientation of the whipstock II has been determined the string S may be turned to bring the whipstock to the correct or desired position.

It is to be observed that the method and apparatus of the invention does not necessitate the employment of expensive or delicate mechanisms in the string S or bit I0. The two surveying operations, that is the operations of the mechanisms A and B, may be carried out in succession without the necessity of withdrawing the instrument I2 from the lwell. It is to be particularly noted that the 'method of the invention is adapted to determine the orientation of .a tool in a truly vertical well bore, which is an operation that cannot be carried out by other methods. The method may be carried out when employing the simple or typical surveying instrument I2. The projection 4I and the fulcrum ring 38 do not interfere with subsequent drilling operations. These parts are easily and inexpensively embodied in the bit I0 or other element of the drilling string.

Having described vonly a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specic details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. Well apparatus comprising a straight tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position relative to the tool, the projection being of limited circumferential extent and being located at one side of the central longitudinal axis of the string, a surveying instrument to be run through the string to project downwardly beyond the tool, and amember on the instrument cooperable with the projection to cause the instrument to incline in a given direction relative to the tool when extending downwardly beyond the tool.

2. Well apparatus comprising a substantially straight tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position' relative to the tool, the projection being of limited circumferential extent and being located` at one side of the central longitudinal axis of the string,

a surveying instrument to be run through the string to project downwardly beyond the tool, and a member on the upper portion of the instrument cooperable with the projection, when the instrument is extending downwardly beyond the tool, to cause the instrument to slope in a known direction relative to the tool.

3. Well apparatus comprising a tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position relative to the tool, a

' fulcrum ring on the interior of the string below the projection, a surveying instrument to be run through the string and through the ring to extended beyond the lower end of the string, and a, part on the instrument cooperable with the projection to cause the instrument to pivot in the ring in a known direction.

4. Well apparatus comprising a tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position relative to the tool, a fulcrum ring on the interior of the string below the projection, a surveying instrument to be run through the string and through the ring to extend beyond the lower end of the string, and a tapered member on the instrument engageable by the projection to cause the instrument to pivot in the ring in a known direction relative to the tool.

5. Well apparatus comprising a substantially straight tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position relative to the tool, the projection being of limited circumferential extent relative to the internal circumference of the string and being entirely at one side of the central longitudinal axis of the string, agusurveying instrument to be run through the string with clearance, a line for running the instrument into the well, a member on the inxstruinent engageable with the projection to causethe instrument to inclinel in a known direction relative tothe tool, and weight means associated with the string for forcing the member into operative cooperation with the projection.

6. Well apparatus comprising a tubular well string, a tool on the string, an internal projection on the string adjacent its lower end in a known rotative position relative to the tool, a surveying instrument to be run through the string, a line for running the instrument into the well, a member on the instrument engageable with the projection to cause the instrument to incline in aknown direction relative to the tool, and weight means associated with the string for forcing the member into operative cooperation with the projection, the weight means comprising a weight on the line, and a slack connection between the weight means and instrument.

THOMAS A. CREIGHTON. 

